Field of the Invention
Embodiments described herein relate to lumen supports having plastically deformable structures.
Description of Related Technology
Vascular prostheses, commonly referred to as stents, are now widely used in interventional procedures for treating lesions of the coronary arteries and other vessels. Such devices generally have a tubular shape and are deployed in a vessel, and are intended to restore and maintain the patency of a segment of a vessel. Previously-known vascular prostheses are generally either self-expanding or balloon expandable, and may vary in size, shape or other characteristics depending on whether the use is for the cardiac vasculature, carotid arteries, renal arteries, superficial femoral arteries, or other vessels.
Self-expanding and balloon expandable stents often have elasticities associated with a relatively large amount of recoil. As such, the stent may be prone to recoil inward after being expanded to its maximum outer diameter. If this recoil is significant, the stent may not remain stationary relative to the passageway, instead migrating to a point of lesser desirability. As a result, serious or fatal injury to the patient may occur.
Another aspect of stents is the size to which they may be compacted through crimping. Stents may be crimped onto a catheter for delivery to a lesion location within a lumen. One manner of crimping involves the application of a force directed in a radially inward direction to force the stent into a compact profile. However, the stent's diameter may tend to recoil to a diameter greater than its minimum diameter. This recoil typically increases as the material's elasticity increases. One disadvantage of this phenomenon is that, with increased recoil after crimping, the stent's delivery profile is increased, thereby limiting the stent's applicability to small vessels that would otherwise be accessible by a stent with a smaller delivery profile. Another disadvantage is that a stent that is not tightly coupled to the delivery catheter may become dislodged at an undesirable location during delivery.
Different material choices for stents or other medical devices offer different advantages and disadvantages. For example, some highly elastic materials have increased strength and/or increased radiopacity when compared to other materials with a lower elasticity, yet suffer from greater recoil than materials with a lesser elasticity. A balance is desired in which beneficial features of such stent materials may be enjoyed while reducing disadvantages such as recoil.